1. Field of the Invention
The present invention relates to a process for producing aromatic polyether ketones and polythioether ketones. Aromatic polyether ketones have been known to be physically superior polymers having excellent heat resistance, mechanical and electrical properties and dimensional stability, and low water absorption. The aromatic polythioether ketone is a novel polymer.
2. Discussion of the Background
As a process for the production a polyether ketone, it is known to react 4-phenoxybenzoyl chloride with boron trifluoride in hydrogen fluoride (U.S. Pat. No. 3,441,538). According to this process, it is required to initiate the reaction at a very low temperature (e.g. -78.degree. C.) and yet it is necessary to conduct the reaction by means of a special reactor, and a very cumbersome operation is required for the recovery of the solvent. As another process, there has been known a process wherein 4,4'-difluorobenzophenone and an alkali metal salt of an aromatic dihydroxy compound are reacted in diphenyl sulfone. However, this process, also, has a drawback that it is necessary to conduct the reaction at a high temperature of at least 300.degree. C. Further, U.S. Pat. No. 3,065,205 discloses a process for polymerizing diphenyl ether with isophthaloyl chloride in the presence of Friedel-Crafts catalyst (AlCl.sub.3) and an aprotic solvent. However, there is no description that it is possible to obtain polyether ketones having a high polymerization degree as described in the present invention. Each process has an additional drawback that the starting material, i.e. 4-phenoxybenzoyl chloride or 4,4'-difluorobenzophenone, is expensive.